Intraperitoneal paravesical spaces: CT delineation with US correlation.

The urinary bladder, obliterated umbilical arteries, and inferior epigastric vessels located within the extraperitoneal space of the anterior abdominal wall indent the anterior parietal peritoneum, forming intraperitoneal paravesical fossae. These are the supravesical space and the medial and lateral inguinal fossae. More posteriorly, the peritoneum covering the bladder is reflected onto the rectum to form the rectovesical space, which is divided by the uterus into an anterior vesicouterine recess and a posterior rectouterine pouch, or cul-de-sac. The cul-de-sac is continuous with the pararectal and ovarian fossae and is bounded posterolaterally by the rectouterine (sacrogenital) folds. These peritoneal compartments form a large potential space for the accumulation of ascites and are separated from the equally large extraperitoneal paravesical spaces by only a thin layer of peritoneum or peritoneum and umbilicovesical fascia. The computed tomographic scans of 100 patients with ascites were reviewed, with particular attention to the differentiation between intraperitoneal and extraperitoneal paravesical collections. The scans of intraperitoneal collections were found to have certain characteristic appearances, including inferior displacement of the distended urinary bladder, visualization of the umbilical folds, and preservation of the preperitoneal fat.